Nowadays, the usage of TVs is not limited to the reception and viewing of TV broadcasts, and they are used for a variety of purposes. For example, by connecting a digital video recorder (DVR) such as a video tape recorder (VTR) and a DVD recorder to a TV, it is possible to view contents reproduced by these external devices. For this reason, many TVs are equipped with one or more external input terminals in addition to an antenna terminal to receive TV broadcasts. A user can switch between these input terminals by operating buttons on a remote control and the TV body.
TVs equipped with a number of external input terminals (many of which are high-end TVs) have the advantage of being able to connect to a number of external devices, such as a DVR and a home-use game machine, at the same time. On the other hand, there is a drawback in that operations become complicated since it is necessary to manually switch inputs. It is also inconvenient to have to change remote controls for each external device and operate it after switching the input.
In view of this, there has been suggested or standardized a technique for automatically switching the input of the TV to another device by transmitting commands between the TV and an external device such as a VTR and a technique for transferring the key entries of the remote control using these commands.
For example, a reproduction apparatus disclosed in Patent Document 1 identified below sends an instruction signal such as an infrared signal to a TV when starting reproduction. This instruction signal is a signal instructing that the input of the TV should be switched to the input terminal of the TV to which the output terminal of the reproduction apparatus is connected. Furthermore, when entering a power-off state, this reproduction apparatus sends, to the TV, a signal to instruct that the input of the TV should be switched to the antenna or tuner. By doing so, it is possible to send, from the remote control for the reproduction apparatus to the reproduction apparatus, an instruction to display a menu screen, and at the same time, to send, from the remote control for the reproduction apparatus directly to the TV, an infrared signal indicating the key code of the remote control. Consequently, it becomes possible to switch the input of the TV to the input terminal thereof to which the reproduction apparatus is connected and thus display the menu screen of the reproduction apparatus on the TV screen.
Note that the AV.link standard (Non-patent Document 1 identified below) specifies commands to allow the interoperability between a TV, a VTR, and the like. According to this standard, the VTR issues a predetermined command to the TV, when the VTR starts reproduction or when the VTR displays a menu screen. By doing so, it is possible to send, from the remote control for the reproduction apparatus to the reproduction apparatus, an instruction to display a menu screen, and at the same time, to send, from the reproduction apparatus to the TV via the AV.link line, a predetermined command to request a screen switch. Consequently, it becomes possible to switch the input of the TV to the input terminal thereof to which the reproduction apparatus is connected and thus display the menu screen of the reproduction apparatus on the TV screen.
After the menu screen is displayed, it is possible to operate the reproduction apparatus by sending, from the remote control for the reproduction apparatus to the reproduction apparatus, an infrared signal indicating the key code of the remote control, as in the normal manner. By doing so, it is possible to avoid having to change the remote control for the TV to the remote control for the reproduction apparatus and operate it after switching the input of the TV to another using the remote control for the TV. In the case where the remote control for the reproduction apparatus is equipped with a TV input switch key, there is no need to change to the remote control for the TV. In this case, too, by pressing the TV input switch key several times, it is possible to save the effort of switching the input of the TV to the signal from the input terminal to which the reproduction apparatus is connected. A CEC line in the HDMI interface disclosed in Non-patent Document 2 identified below can also realize the same functions.
Note that Non-patent Document 3 identified below specifies commands to transfer key codes of a remote control between devices which are connected under IEEE 1394 standard. According to this specification, for example, by transferring, using predetermined commands, key codes of the TV remote control such as “up”, “down”, “left”, “right”, “enter” and the like to a device which displays a menu screen on a TV screen, it is possible to operate that device with the TV remote control.    Patent Document 1: Japanese Laid-Open Patent Application No. 2000-350131    Non-patent Document 1: CENELECAV.link (EN50157-1, EN50157-2-1, EN50157-2-2, EN50157-2-3)    Non-patent Document 2: HDMI Specification 1.1 (CEC Supplement)    Non-patent Document 3: IEEE 1394 Trade Association TA Document 2001001 AV/C Panel Subunit Specification 1.1